MeSH definition : A radioactive element of the actinide group of metals. It has the atomic symbol Pa,
atomic number 91, and atomic weight 231. It decays by alpha-emission.;
MeSH CAS label : protactinium;
MeSH Related Number : 7440-13-3 (Protactinium);
Registry Number MeSH : 7440-13-3;
MeSH annotation : naturally radioactive; IM;
Wikipedia link : https://en.wikipedia.org/wiki/Protactinium;
A radioactive element of the actinide group of metals. It has the atomic symbol Pa,
atomic number 91, and atomic weight 231. It decays by alpha-emission.